1. Field of the Invention
The present invention relates generally to fluid flow control and regulation devices and, more particularly, to one-way flow control devices and valves for pressurized fluids, especially gas. Specifically, the present invention relates to such flow control devices particularly adaptable as inlet valves for first and second stage regulator members used in scuba diving units to prevent the entry of water and other contaminates into the regulator member without interfering with the proper flow of breathable gas.
2. Description of the Prior Art
Fluid flow regulator and control devices of various types are well known in the art. Both liquid and gas regulator devices have been adapted for a wide variety of commercial and industrial assemblies and apparatus. However, the adaptation of such devices to high-pressure environments having relatively small fluid control apertures and valves is highly specialized. This is particularly true in the field of scuba (self-contained underwater breathing apparatus) diving equipment and regulators.
Within the past several decades, the sport of scuba diving has enjoyed considerable popularity so that there exists an entire industry for supplying equipment for the sport. Moreover, the popularity of the sport continues to increase dramatically. This industry manufactures and sells a wide variety of instruments, devices and equipment to enable a person to properly breathe underwater and remain beneath the water's surface for extended periods of time. One of the most vital concerns in the manufacture of underwater breathing apparatus is the need for a source of air or other breathable gas mixtures at substantially constant pressure. That is, in order to allow a person to breathe properly, it is necessary to have a source of air or other breathable gas, the pressure of which does not fluctuate randomly at the point of intake.
Typically, scuba divers utilize a pressurized source of breathable gas, such as compressed air as well as mixed gas blends, at a relatively high initial pressure which may exceed 3,000 psi and even reach 4500-5000 psi in certain technical diving situations. Pressure regulators have been developed over the years to deliver such breathable gas to a diver at ambient pressure regardless of the depth of the scuba diver. Consequently, the breathable gas is typically reduced in pressure in staged steps. The first step is performed by a first stage regulator member of a dual stage regulator assembly which reduces the tank pressure of approximately 3,000 psi or greater to a constant intermediate pressure of about 120-140 psi. The first stage regulator is mounted directly to the high pressure source of gas, such as a scuba tank outlet valve, and the intermediate pressure gas is then directed through a pressure hose exiting the first stage regulator member.
The intermediate pressure gas from the pressure hose is then delivered to a second stage regulator member which generally has a diaphragm arrangement to further reduce gas pressure and provide breathable gas to the diver at a usable, that is ambient, pressure. The second stage regulator member may be in the form of a primary regulator utilized by the scuba diver as a primary source of breathing gas, or it may be in the form of what is commonly called an alternate gas or air source, or an octopus. The alternate air source is utilized for emergency breathing situations and is frequently combined with an inflator valve for use with buoyancy control devices. Moreover, intermediate gas pressure lines or hoses may also extend from the first stage regulator member to provide gas for other purposes, such as use with a dry exposure suit and the like.
Once the dual stage regulator assembly is attached to a scuba tank gas outlet valve to create an entire scuba unit, the scuba unit is an environmentally closed or sealed system. In other words, the system wherein compressed gas passes from the tank through the first stage regulator, the intermediate pressure hoses and to the inner side of the second stage regulator member diaphragm, is limited only to compressed gas and is not exposed to the environment in any manner. The exterior or outer side of the second stage regulator member diaphragm, however, is exposed to the ambient environment, including water. It is essential, then, that the regulator assembly gas delivery system remain dry both during its use when connected to a scuba tank as well as when it is not being used and is disconnected from a scuba tank. Otherwise, contaminants, such as salt water, fresh water, wash water, airborne particulates and the like, will contaminate the assembly if allowed to enter the interior of the regulator assembly, such as at the gas inlet opening. Such contamination can include the rusting and corrosion of internal metal air filters and other internal parts of the regulator assembly as well as possibly clogging small apertures or orifices and thus preventing the regulator assembly from operating properly if even at all.
While it is simple to observe how a regulator assembly can remain dry when fully installed to a scuba tank and in use, a problem occurs once the regulator assembly is disconnected from a tank after a dive is over. As previously mentioned, the gas in the tank is delivered to the first stage regulator member through a tank outlet valve. There are two basic and most common types of valve connection arrangements between a scuba tank and the first stage regulator member which are standard in the art. However, other less common connection arrangements are also available, such as those utilized in technical diving and rebreather units. The first typical connection is the most common and is known as a yoke connection wherein the first stage regulator member has a round opening plugged by a metal filter surrounded by a raised collar with an O-ring thereabout. In this arrangement, the tank outlet valve has a small aperture at the middle of a round recessed area, the raised collar snugly fitting within the recessed area so that the O-ring is fitted against it. A yoke fitting is secured to the first stage regulator member and surrounds the tank outlet valve, and a hand knob is hand tightened against the back of the tank valve to force the raised collar against the round recessed area so that the O-ring is snugly compressed therebetween. The second common connection arrangement is called a DIN valve connection wherein the first stage regulator member simply screws directly into the tank valve outlet opening using five or seven threads depending upon the pressure to be contained within the tank.
Heretofore, a dust and water cap, has generally been used as standard equipment for covering the opening of an air pressure inlet valve of the first-stage regulator member when the regulator is not in use. The dust cover is typically either plastic or rubber and is held in place by the yoke and hand knob. Moreover, the valve connection of the DIN valve arrangement as well as the alternate air source for the intermediate pressure hose also generally have removable caps which cover the inlet opening when not in use. When a scuba diver completes his or her diving, the gas cylinder valve is released from the regulator inlet valve. At this time, ideally the dust and water cap is attached to the top of the air inlet valve to prevent water and contaminates such as described above from entering the air inlet valve and contaminating, rusting and/or corroding the internal air filter and other internal parts inside the valve. Unfortunately, as can be imaged, divers often forget to install the dust cap on the air inlet valve and/or the cap on the alternate air regulator member inlet, and the internal regulator filter then becomes contaminated when the scuba equipment is washed down after a dive or later when the valve is exposed to outdoor elements. This is particularly true of new or student divers. The contamination can cause a gas restriction inside the regulator assembly and a potential breathing hazard to the diver. Also, the gas restriction can cause the high pressure gas to break apart portions of the air filter, which can cause internal damage and failure of working parts inside the regulator assembly. Further, water entering the regulator assembly at either the first or second stage regulator members can cause internal rusting and corrosion of the working parts and failure of the regulator. While significant technical advances have been made over the years since the advent of the scuba diving system, this problem of preventing inadvertent or negligent contamination of the regulator system has never been satisfactorily addressed. In almost 60 years of scuba diving equipment development, a dust cover manually put into place by the diver is the best that has been achieved to date.
U.S. Pat. No. 4,226,257, No. 5,685,297 and No. 5,687,712 all disclose scuba diving regulator assemblies and valves therein, but none address the problem discussed above nor are they directed to regulator inlet valve construction in any particular manner. Consequently, there remains a significant need in general and more specifically in the diving industry, for a fluid, and in particular breathable gas, control system that will allow gas to flow into regulator members as required yet prevent any fluid or particulate contaminants from passing into the regulator inlet valves inadvertently without requiring one to remember to physically place a cover or cap over the inlet valve when not in use. The present invention addresses this significant problem in fluid flow systems in general and more particularly in the use of breathable gas regulators for scuba diving systems, oxygen delivery systems, emergency breathing systems and the like.